Two decades after declaring an official war on air pollution, Thailand is losing the battle. Despite a flurry of committees and high-profile promises, crucial indicators show that the sources of the smog and its deadly health impacts are rising once again. What began as a seasonal nuisance in the northern highlands has metastasised into a year-round national health crisis that threatens the very fabric of Thai society.
In 2007, General Surayud Chulanont’s government established the national anti-smog centre to combat mounting haze in the North. While its launch initially brought hope, citizens have learned the hard way that authorities lack the political will to guarantee safe air. Today, the sky over Chiang Mai – once a pristine tourist haven – is frequently shrouded with a grey veil of toxic particulate matter.
Left unprotected, Thais have been forced to adopt their own defensive measures, relying on face masks and air purifiers. Yet respiratory problems and smog-linked health cases continue to climb. The northern capital of Chiang Mai has regularly topped global air pollution rankings in recent years. And as the crisis deepens, the threat of PM2.5 has spread from the North to every other corner of the country, including the industrial belts of the Eastern Economic Corridor and skyscraper canyons of Bangkok.
The invisible killer: How PM2.5 operates
PM2.5 – dust particles smaller than 2.5 micrometres in diameter – are so tiny that they bypass the body's natural filtration systems. They lodge deep in the lungs and enter the bloodstream directly, triggering systemic inflammation.
“I have lung patients whose conditions worsen rapidly every time the air quality drops,” reported Assoc Prof Dr Atikun Limsukon of Chiang Mai University’s Faculty of Medicine. The medical community is sounding the alarm: this is no longer just about "itchy eyes", but surging lung cancer rates and early-onset cardiovascular disease among non-smokers.
Prof Dr Arintaya Phrommintikul, director of Maharaj Nakorn Chiang Mai Hospital, noted that patients seeking treatment for nosebleeds and eye irritation rise 1.5 times during the smog season, typically from January to April. “Statistics over the past three years have confirmed the link between smog and health problems,” she said. Citing research, Arintaya stated that every 10-microgram increase in PM2.5 per cubic metre raises the risk of cardiovascular disease and stroke by 6% to 8%.
Based on state hospital records, the Public Health Ministry reports that roughly 10 million Thais fall ill every year with PM2.5-related conditions. However, activists argue these figures are just the tip of the iceberg, as they exclude millions seeking treatment at private clinics or those in rural areas who suffer in silence.
The gaps letting smog in
Despite two decades of growing crisis, Thailand still lacks a central authority empowered to enforce clean-air targets. Instead, responsibility is fractured across departments: the Ministry of Natural Resources handles forests, the Ministry of Agriculture handles farm waste burning, and the Ministry of Industry handles factories.
The main drivers of PM2.5 are wildfires and agricultural burning. Over the past four months, GISTDA has detected 84,627 hotspots across the North, attributed mostly to agricultural clearance. This resurgence reflects the failure of state measures: hotspots peaked at 109,305 in 2023, declined to 55,589 in 2025, but have risen sharply again this year. Chiang Mai residents complain that efforts to contain spreading fires are hampered by a severe lack of government funding and equipment.
The blame game
Suchart Chomklin, minister of Natural Resources and Environment, has blamed the surge in forest fires on drought and foragers. “People light forest fires when they forage for food. This behaviour pollutes the environment,” he lamented. By framing the issue as one of "ignorant foragers", the state shifts the blame onto the most vulnerable.
However, Prof Pinkaew Laungaramsri of Chiang Mai University argued that the crisis is structural. “This involves cities, industries, agriculture, and cross-border pollution,” she explained. Pinkaew pointed out that air pollution shrouds northern skies year-round, fed by industrial zones and neighbouring countries as much as dry-season fires. She added that more research is needed to identify the precise percentage of smog generated by each source. “Currently, there is no clear information on this,” she noted.
The failure of ‘Zero Burning’
In April, the Chiang Mai Breath Council (CMBC) highlighted a lack of unified action in response to the record-breaking 2026 smog. It added that the government’s “Zero Burning” policy — a blanket ban on outdoor fires — is counterproductive because it turns residents into opponents rather than supporters of anti-smog efforts. By making all fire illegal, farmers now burn fields at night to avoid detection, creating "smoke bombs" that settle in valleys and are harder to manage than controlled burns. The CMBC has urged authorities not to criminalise farmers, but instead to tackle root causes like the contract farming systems that force them to clear their fields in the cheapest way possible – with fire.
The Clean Air Bill: A choice of values
Millions hope the Clean Air Bill, which includes a “Polluters Pay Principle”, will finally provide legal teeth. However, concerns are growing that it will be killed at birth.
The bill had passed through the Lower House and was awaiting Senate approval when Parliament was suddenly dissolved last year, leaving the legislation pending. If the government fails to endorse it for Senate review by May 13, it will be thrown out, forcing supporters to restart from square one.
Minister Suchart has pledged support but with industry-friendly caveats, insisting it must not obstruct investment. The Thailand Clean Air Network believes the minister is worried the bill would mirror Singapore’s Transboundary Haze Pollution Act by imposing heavy fines on polluting businesses.
The Clean Air Bill would hold big corporations accountable for encouraging agricultural burning while reducing penalties for small-scale farmers. The network brushed off concerns that the bill would hurt the investment climate, competitiveness, and economy.
“The government cannot view this issue solely through the lens of investment; it must prioritise the lives of its citizens,” the network stated, posing a final question: “Does Thailand’s economic competitiveness matter more than the health of its people?”
